The present invention relates generally to the art of water disinfecting, and in particular to a novel bactericidal mixed-form polyhalide resin.
Several techniques are known for killing bacteria in water. One such method includes treating the water with halogens, but because this method leaves large residual concentrations of halogens in the treated water, its usefulness has been limited to the treatment of swimming pools and the like. Another method involves the use of polyhalide resin bactericides of one single form or another. For example, bromine can be eluted from a strong base anion-exchange resin at concentrations ranging from 10 to 10,000 p.p.m. Residual bromine is captured by a scavenger resin to reduce the final bromine level to 1.0 p.p.m. or below. Another water disinfecting technique involves the use of an anion-exchange resin fully loaded with triiodide (I.sub.3.sup.-) ions.
The latter technique, while being useful for a wide variety of different feed waters, has one drawback when the feed solution contains relatively high salt concentrations, i.e., 250 p.p.m. as sodium chloride or greater. While little free iodine is eluted from the resins, relatively large quantities of iodide ions are eluted. A resin which elutes reduced levels of iodide ions under these conditions would be a significant improvement in this water treatment technology.